Facing Brick Specification Guide
Weatherproofing
WEATHER PROOFING
Design and detailing to prevent moisture crossing the cavity are of paramount importance. The following recommendations are intended to prevent moisture crossing to the inner leaf of the wall. a.
Use the correct designation of mortar as recommended in PD 6697:2001 and hEN 1996:2006. See page 37.
b.
Take all necessary design precautions to minimise the effects of movement. See page 38 and39 relating to movement control.
c.
Provide weep holes in the outer leaf immediately beneath the ground level damp-proof course. Weep holes can be provided by omitting the mortar in a perpend joint.
Suitable spacing for weep holes is at intervals of every 3rd perpend. Clear weep holes should be provided wherever there is extensive bridging of the cavity to safeguard against a build up of water and thus penetration to the internal skin.
d.
Ensure the horizontal and vertical damp-proof courses are correctly positioned, adequately long and stepped outwards. Damp-proof course should extend through the full thickness of the leaf and preferably project beyond the face and should not be bridged by pointing or render. Failure to lap damp-proof courses reduce their efficiency. Recommended minimum lap is 100mm as per PD 6697:2001 and hEN 1996:2006.
e.
Ensure chimneys have effective d.p.c. to eliminate the possibility of water penetrating the fabric. See right for effective waterproofing of chimneys.
f.
Use the brick stretcher calculation table on page 35 to ensure the position of window/door openings etc. correspond with brick work.
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